Genetics in neonatal surgical practice
Prem Puri in Newborn Surgery, 2017
Gene tracking analysis in the family uses the property of normal variation in a gene between different people. Some genetic areas show wide variation between individuals, and a DNA marker from such an area, which can detect many variations, is described as being polymorphic. Each variant of a polymorphic marker is known as an allele. There are now thousands of polymorphic markers covering most of the human genome, and such markers can be found very close to most known genes. There are several types of polymorphic DNA markers, including markers characterized by different numbers of specific DNA-cutting enzymes recognition sites or restriction fragment length polymorphisms (RFLPs). Other markers detect the variation in the number of anonymous elements of repetitive DNA and are called microsatellites or minisatellites.
Analysis and Interpretation
John M. Wayne, Cynthia A. Schandl, S. Erin Presnell in Forensic Pathology Review, 2017
The correct answer is E. 7402. The combined paternity index, also known as genetic odds in favor of paternity, is calculated by determining which genetic marker each person has in common. This is done by looking at each “system” and seeing if a common locus exists. For example, the D8S1179 system has a shared allele (in this case, 14) between the child and alleged father, so it is used in the calculation. Once it is determined which systems are matched then the paternity index is multiplied by each other. The paternity index is a calculated value generated for a single genetic marker or locus (chromosomal location or site of DNA sequence of interest). In our example, all of the systems had one shared allele and are multiplied together yielding 7402.38 as the product that rounds to 7402. Of note the AMEL system does not have a number since it is used to define sex of the individual and is assumed to be 1. Another way of saying this is that the odds are 7402 to 1 that the alleged father is not the father. All of the other answers are incorrect as they do not yield the correct calculation. Choice A is the probability of paternity, not the combined paternity index. Choice B is the indices added instead of multiplied.
A Brief Survey of Early Indigenous Knowledge Which Influenced Modern Agronomic Practices
David R. Katerere, Wendy Applequist, Oluwaseyi M. Aboyade, Chamunorwa Togo in Traditional and Indigenous Knowledge for the Modern Era, 2019
The indigenous farmers from the region were able to use their knowledge to correctly distinguish tetraploid (Solanum tuberosum ssp. andigena) and diploid (S. goniocalyx, S. phureja, and S. stenotomum) species without any modern methods such as chromosome counting or isozymes (Quiros et al. 1990). This indicated, at least in part, that folkloric methods of selection for this crop were effective. At present, distinguishing between diploid, triploid, and tetraploid forms of the potato is achievable through the use of a range of sophisticated approaches, including electrophoretic (Bauw et al. 2006), flow cytometric (Uijtewaal 1987), and cytogenetic (Dong et al. 2000) methods. DNA marker technologies (Bryan et al. 1999, Nakagawa and Hosaka 2002, Hardigan et al. 2017) are now used for rapid and accurate selections of distinct forms of the potato in genetic improvement programs.
Preimplantation genetic testing in two Danish couples affected by Peutz–Jeghers syndrome
Published in Scandinavian Journal of Gastroenterology, 2023
Anna Byrjalsen, Laura Roos, Tue Diemer, John Gásdal Karstensen, Kristine Løssl, Anne Marie Jelsig
Opting for PGT-M can confer technical challenges; PGT-M in Denmark is based on either genetic marker analysis, direct testing for the pathogenic variant, or a combination of both. A genetic marker analysis is a microsatellite polymorphic marker analysis, which essentially is a screening for the allele on which the pathogenic variant is located. In order to establish a microsatellite polymorphic marker analysis, DNA from a minimum of two affected relatives are needed to ensure identification of the specific allele carrying the pathogenic variant. Additionally, it is not always technically possible to establish the markers, despite having DNA from two affected family members. The chance of achieving a pregnancy through PGT-M has increased in recent years, going from a 20 − 25% chance for each blastocyst transfer to roughly 40% today [13], but PGT-M is time consuming, making the option of PGT less attractive for patients who are eager to achieve a pregnancy within a short time frame.
Gemcitabine induced cytotoxicity, DNA damage and hepatic injury in laboratory mice
Published in Drug and Chemical Toxicology, 2020
Waleed A. Q. Hailan, Faisal M. Abou-Tarboush, Khalid M. Al-Anazi, Areeba Ahmad, Ahmed Qasem, Mohammad Abul Farah
DNA, from liver cells, was extracted from both treated and control mice by using the tissue and cells genomic Prep Mini Spin Kit (GE healthcare life sciences, UK). The concentration and purity of the DNA thus extracted was determined by reading the absorbance at 260 nm, and protein contamination estimates were based on the ratio of absorbance at 260/280 nm. For the analysis of DNA laddering, 1% agarose gel was prepared, and the DNA was separated by electrophoresis. An equal amount of DNA from the treated and control group was mixed with 1X tracking dye (bromophenol blue) and loaded into wells of agarose gel. A standard 100 base pair DNA marker was also loaded in order to compare the DNA laddering. After the electrophoresis, the DNA was stained with 20 µg/ml of ethidium bromide and the gel was visualized under UV light and photographed using a Gel Doc XR System (Bio-RAD Lab. Milan, Italy).
Prenatal reflex DNA screening for trisomy 21, 18 and 13
Published in Expert Review of Molecular Diagnostics, 2018
With the recall method, women are given a screening result based on the Combined test (positive or negative). Using a risk cut-off of 1 in 150 to define a positive Combined test, about 3% of women screened are recalled for counseling and worried by being told they have a positive result. With the reflex method, this worry is avoided because the Combined test result is only reported if it is negative; a positive test result is not reported at this stage. Instead, a DNA analysis on the plasma sample already provided is automatically triggered, that is, reflexed. The Combined test risk cut-off that triggers the DNA analysis is ideally lower than that used in the recall method, to increase the detection rate because, in contrast with the recall method, lowering the Combined test risk cut-off has a minimal effect on the false-positive rate [2]. The reflex DNA test result amalgamates information from the Combined test markers with the DNA marker, and a positive or negative screening result is issued accordingly. With the reflex method, few women with unaffected pregnancies receive a positive screening result and the cut-off used to trigger a DNA analysis can be reduced as DNA analysis becomes less expensive and more robust.
Related Knowledge Centers
- Amplified Fragment Length Polymorphism
- DNA Sequencing
- Gene Mapping
- Minisatellite
- Restriction Fragment Length Polymorphism
- Gene
- Chromosome
- Species
- Single-Nucleotide Polymorphism
- Random Amplification of Polymorphic DNA